Anime adaptation:

Plot

Deep inside the Diclonius Research Institute, Arakawa is led into a freezing storage chamber by Chief Kakuzawa, who explains that today is the day for their plan to eradicate all non-horned humans goes forward, not with a nuclear weapon as she expected, but with a biological one that he thinks is more thorough and final. A terrible feeling washes over her, despite the idea that she will be hailed as a genius scientist for thousands of years by this new species.

Meanwhile, in Kamakura, the now infantile Mariko runs joyfully towards Kurama, only to stumble and fall flat on her face, and then start to cry the way that any young child would. Nana explains her behavior as being exactly like the change from Lucy to Nyu, with even the Diclonius presence masked, and the subject unable to use their vectors. He then realizes that this is his chance to end the grievous threat that she poses and prepares to kill her, seeing visions of what her childhood could have been like as she feverishly hugs him by the leg. Nana disassembles his gun, saying that Kurama should teach her right from wrong, and love her so that she can learn to live among people. He realizes that Nana is correct, but the tender scene is interrupted by Shirakawa's arrival, telling him that Chief Kakuzawa's master plan is going forward, even as they speak.

Back at the Institute, Arakawa views a container, the contents of which act as an intense distillation of the Diclonius virus. The Chief intends to detonate the missile in the atmosphere over Japan, with wind currents and the new infections spreading the birth of Diclonius children all over the world, bringing humanity's numbers down dramatically in short order. A false weather satellite launch will serve as the means by which he will detonate the virus over Tokyo Bay, ensuring at least twenty million infections in one stroke. Before a worried Arakawa, he declares this day to be the end of human history and the start of Diclonius history.

Trivia

Like in Episode Thirteen, Kurama has visions of Mariko if she had been born a regular human.

On this adorable chapter cover, both Mayu and Wanta are waving at the reader. Mayu once again seems to be depicted in the clothing she was first seen in, which later on shows up more often in art outside the story than it ever did within it.